Art of cleaning carpets



United States Patent 3,418,243 ART OF CLEANING CARPETS Orville D. Hoxie, Grand Rapids, Mich, assignor to Bissell Inc., Grand Rapids, Mich., a corporation of Michigan No Drawing. Filed Jan. 4, 1965, Ser. No. 423,345 4 Claims. (Cl. 252-154) ABSTRACT OF THE DISCLOSURE The invention relates to a dry cleaning composition for carpets, composed of a finely divided inert carrier, a volatile organic solvent, a water soluble surfactant and water. The formulation is in the form of a powder which is only slightly moist to the touch but is essentially free flowing. When applied to the carpet, the inert carrier functions as a fiber scouring medium, while the solvent attacks greases and oils and the aqueous phase serves to dissolve water soluble soil. Upon evaporation of the solvent and water, the soiled particles are adsorbed on the surface of the carrier and the resulting residue can be readily removed from the carpet by sweeping or vacuuming.

This invention relates to a composition for cleaning carpets, and more particularly to a dry cleaning composition for cleaning carpets in situ.

When cleaning carpets on the floor or in situ, it is desirable to use a minimum amount of water in order to reduce the drying period and eliminate the possibility of mildew occurrence. A common method of cleaning carpets in situ is to apply a foamed aqueous detergent solution to the carpet. The detergent foam is brushed into the carpet to loosen the soil and the soil particles are encapsulated in the foam bubbles. On drying or evaporation of the aqueous phase, a dry, fluffy residue remains which contains the soil. The residue can be readily removed from the carpeting by sweeping or vacuuming.

While the use of the foamed detergent solution substantially reduces the amount of water applied to a carpet, there are situations where even this amount of water is undesirable. For example, Where the carpet is used in public or commercial establishments such as theaters, hotels, ofiices and the like, the drying time should be maintained at a minimum to permit resumption of traffic in the shortest possible time.

The present invention is directed to a dry cleaning composition for carpets, which is composed primarily of an inert carrier, a volatile organic solvent, a Water soluble surfactant and Water. The formulation is in the form of a powder, or a finely divided solid material, which is only slightly moist to the touch but is essentially free flowing. When applied to the carpet, the inert carrier functions as a fiber scouring medium, while the solvent attacks greases and oils and the aqueous phase serves to dissolve water soluble soil. The surfactant acts as a partial emulsifier for the solvent, as well as reducing the surface tension of the water phase plus providing detergent action. Upon evaporation of the solvent and the water, the soil particles are adsorbed on the surface of the carrier particles and the resulting residue can be readily removed from the carpet by sweeping or vacuuming.

The dry cleaning formulation of the invention has both an organic solvent phase and an aqueous phase which cooperate to attack and remove various types of soil. As the composition itself is essentially dry in nature and contains a minimum amount of water, there is less tendency to damage the overall construction than when using a liquid detergent.

As the cleaning formulation is substantially dry, the in place drying time for the formulation and the carpet is ICC minimized. After removal of the residue, the carpet can be immediately Walked upon. This quality is particularly advantageous for commercial establishments, such as hotels, theaters, oflice buildings and the like.

The cleaning composition is also useful in touch-up cleaning, for the limited carpet area to be cleaned can be feathered in with the uncleaned portion so that the cleaned area is virtually unnoticeable. Touch-up cleaning is very difficult when using a liquid or foam detergent, for the area cleaned tends to show an obvious line of demarcation.

The cleaning composition of the invention has the following general formula in weight percent and based on active ingredients:

The carrier to be used in the composition is an inert, absorbent material having a large surface area per unit volume and a low bulk density. It is important that the carrier have a white or light color, for a light color pro vides distinct advantages when using the composition. A White or light colored material has a certain initial appeal to the user and secondly, as most carpeting is non-white, a whitish material when sprinkled on the carpeting can be readily seen so that the area on which the material has been distributed is readily visible. Conversely, efiiciency of subsequent removal from the carpet is also readily determined.

In addition, as the material picks up soil, the whitish color will change to dark gray, indicating to the user that the material is picking up and adsorbing the soil from the "carpet.

It is also important that the carrier be a lightweight material having a low bulk density generally in the range of 7.5 to 20 lbs. per cu. ft. in a loose or non-compacted state. A greater bulk density Will mean that the particles are relatively dense and will not have suflicient capacity to adsorb the soil.

The particle size of the carrier is also important because the composition is used not only for cleaning, but has to be retrieved or removed after the cleaning operation. It has been found that the particle size should be such that only 1% of the particles have a size smaller than 2 microns and not more than 15% of the particles have a size greater than 40 microns. A mesh particle size falling within these limits provides a material that can be readily distributed on the carpet and yet can be easily retrieved from the carpet by vacuuming. If the particle size is too small and the carrier contains a substantial proportion of fines, dusting will be a problem when the carrier is applied to the carpet. If the particle size of the carrier falls above the above-mentioned limits the material is more diflicult to apply and spread over the carpet and the surface area is decreased so that the overall absorptive characteristics are reduced.

Specific examples of the materials that can be employed as the inert carrier are diatomaceous earth, ground corncob, ground cork, talc, sawdust, fullers earth and the like. Diatomaceous earth in particular provides a very excellent carrier, for it has a low bulk density, a white or whitish color and the desired particle size.

The solvent to be used in the composition can be any conventional volatile solvent which is commonly used for oils and greases. The solvent should be a non-oily type and 100% volatile at room temperature so that it will be completely eliminated from the carpet by evaporation. In addition, the solvent should be reasonably free from flash and fire hazard, non-toxic and non-harmful to humans and to the materials of the carpet fabric or backing construction.

The volatility of the solvent is important to the overall composition. The volatility must be such that the solvent will remain in place during cleaning of the carpet to dissolve the greases and oils, and yet will volatize completely in a period of 15 minutes to one hour. To provide the desired characteristics, the solvent generally should have an initial boiling point in the range of 300 to 340 F., a distillation end point in the range of 380 to 470 F. and a flash point above 100 F.

Specific examples of solvents which can be used are petroleum distillate and petroleum distillate blends, chlorinated hydrocarbons, such as l,l,1-trichlorethane, perchlorethylene, glycol ethers, such as ethylene glycol moxo-butyl ether, and the like. The solvent phase can include blends of each class as well as a blend within a class.

The surfactant is a water soluble material which serves to reduce the surface tension of the water and also acts to a degree as an emulsifier for the solvent. While the surfactant itself does not provide a good emulsion, it does sufficiently emulisfy the solvent so that there is no distinct separation of the phases when the composition is applied. It is important that the emulsifier surfactant be chosen with care since certain classes of emulsifiers provide a tacky or sticky residue which cannot be removed by evaporation and cause the carpet to be readily resoiled.

The surfactant should dry to a particulate or crystalline residue which can be easily retrieved by vacuuming; should be non-tacky in order not to present a resoil potential to the carpeting; and should have an effective detergency action. Examples of the surfactants which can be applied are alkali metal alkyl sulfates, designated by the formula ROSO X where R is an aliphatic hydrocarbon having a carbon range of to 18, and including both saturated and unsaturated forms, and X is an alkali metal selected from the group consisting of sodium potassium, lithium and the like. A specific example is sodium lauryl sulfate.

Another group of surfactants which can be employed is the alkali metal alkylol sarcosinates which have the general formula RCON(CH )CH COOX where R is an aliphatic hydrocarbon group having a carbon content of 12 to 18 and X is a hydrogen atom or a water soluble salt forming cation such as sodium, potassium, lithium and the like.

Acetylenic glycols, such as those disclosed in US. Patent 2,997,447, can also be used as the surfactant.

Other detergents or surfactants which can be employed are the water soluble higher alkyl aryl sulfonates, particularly those having about 8 to 15 carbon atoms in the alkyl group. It is preferred to use the higher alkyl benzene sulfonate detergent for optimum effects, though other similar detergents having a mononuclear aryl nucleus, such as toluene, xylene, or phenol, may be used also. The higher alkyl substituent on the aromatic nucleus may be branched or straight-chained in structure, examples of such groups being nonyl, decyl, dodecyl, tridecyl, and pentadecyl groups derived from polymers of lower mono-olefins, decycl, keryl, and the like.

The sulfate and sulfonate detergents are used in the form of their water soluble salts, such as the alkali metal and nitrogen-containing, e.g. lower alkylolamine salts. Examples are the sodium, potassium, ammonium, isopropanolamine, monoand tri-ethanolamine salts of said higher alkyl benzene sulfonate, higher alkyl sulfate and the like. In commercial practice, it is preferred to use the alkali metal and/or ammonium salts.

Further suitable non-ionic detersive materials are the higher fatty acid alkanolamides, such as the monoethanolamides, diethanolamides and isopropanolamides wherein the acyl radical has about 10 to 18 carbon atoms. Examples are coconut (or equivalent lauric), capric and myristic diethanolamide, monoethanolamide and isopropanolamide.

The liquid phase, including the water, solvent and surfactant, comprises from 25% to 50% of the composition. It has been found that if the liquid concentration is increased above 50%, the material will be mushy and will be more dificult to handle and apply. Conversely, if the Water content decreases below 25% the material is too dry and powdery and dusting will be a problem accompanied by less effective cleaning properties.

A water emulsion of dimethyl silicone oils canbe added to the composition as a lubricant to reduce the internal cohesion between the particles of the carrier and while permitting the particles to be spread more easily over the carpet.

In addition to the lubricant, small amounts, up to 1%, of conventional optical brighteners, preservatives, germicides, insecticides, and the like, can be added to the composition without materially affecting the overall properties or characteristics of the composition.

The formulation is generally prepared by blending the surfactants, the water, and the solvent into a liquid emulsion and the emulsion is then added to the inert carrier and mixed therein to provide the completed product.

In cleaning a carpet, the dry formulation is manually distributed over the area of the carpet to be cleaned and is generally worked or brushed into the carpet by a suitable applicator or other device. As previously mentioned, the solvent serves to dissolve oils and greases while the water phase will dissolve water soluble soils. In addition, the mechanical brushing action will lift inert soil particles such as metal oxides, clay and carbon dust and these materials along with the residue from the evaporation of the solvent and the water are absorbed on the surface of the carrier particles. After a period of about 15 minutes to one hour, depending on the relative humidity, ambient temperatures, the condition of the carpet and other factors, the solvent and water have completely evaporated, leaving the dry carrier particles. The carrier particles are then removed from the carpet either by vacuuming or by sweeping.

The formulation of the invention provides physical properties which are adapted specifically for cleaning carpets in situ. The dry formulation contains both an organic solvent phase and a water phase which will attack and remove both oils and greases and water soluble soils. Moreover, the powdery carrier provides a scouring action for the carpet nap and also serves to absorb the soils after evaporation of the solvent and the water phase. By using a whitish or light colored carrier, the areas to which the composition has been applied can be readily seen, and as the carrier absorbs soil, the color will darken, indicating to the user that the composition is removing the soil.

The specific formulation of the invention also provides the necessary lubricity for the composition so that it can be readily applied to the carpet and brushed over the surface. In addition, the material can be readily retrieved from the carpet after evaporation of the solvent and water by vacuuming with a minimum of atmospheric dusting.

The following specific examples show the formulation of the dry cleaning composition of the invention:

EXAMPLE NO. 1 1

Percent Diatomaceous earth 60 Deodorized petroleum distillate 6.4 Sodium lauryl sulphate 3.6 Sodium lauroyl sarcosinate 1.2 Acetylenic glycol (Surfynol 61) 0.20 Silicone emulsion (SM62) 0.10 Preservative (Dowcide A) 0.08 Optical brightness 0.01 Water 28.40

This formulation was prepared by initially mixing the petroleum distillate, the sodium lauryl sulphate, sodium lauroyl sarcosinate, Surfynol 61, the silicone emulsion, the Dowcide A and water to provide an emulsion, and the emulsion was subsequently added to the diatomaceous earth and mixed therein to provide the finished composition.

EXAMPLE NO. 2

A dry cleaning composition was prepared having the following composition in weight percent:

The above composition was prepared in a manner similar to that of Example No. 1.

EXAMPLE NO. 3

A composition was prepared which was similar to Example No. 2 except that fullers earth was substituted for the diatomaceous earth and dodecyl benzene sulfonic acid was substituted for the sodium myristyl sulfate.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim:

1. A composition for cleaning carpets in situ, consisting essentially by weight of 50 to 75% of diatomaceous earth, 4 to 15% of a volatile hydrocarbon solvent capable of dissolving greases and oils and having an initial boiling point in the range of 300 to 340 F., a distillation point in the range of 380 to 470 F., and a flash point above 100 F., 0.25 to of a water soluble surfactant characterized by the ability to dry to a fluify residue, and 10 to 40% water.

2. The composition of claim 1, wherein said diatomaceous earth has a bulk density in the non-compacted state in the range of 7.5 to 20 pounds per cubic foot and has a particle size such that not more than 1% has a size smaller than 2 microns and not more than 15% has a size greater than 40 microns.

3. The composition of claim 1, wherein said water soluble surfactant is selected from the group consisting of an a kali metal alkyl sulphate where the alkyl group contains from 10 to 18 carbon atoms, an alkali metal alkylol sarcosinate where the alkylol group contains from 12 to 18 carbon atoms, an acetylenic glycol, an alkyl aryl sulfonate where the alkyl group contains from 8 to 15 carbon atoms, a fatty acid alkanolamide where the acyl radical has from 10 to 18 carbon atoms, and mixtures thereof.

4. A composition for cleaning carpets in situ, consisting essentially of a solid phase and a liquid phase, said solid phase consisting essentially of diatomaceous earth having a bulk density .in the non-compacted state of 7.5 to 20 pounds per cubic foot, and said liquid phase being mixed with said solid phase and consisting of from 25 to by weight of the mixture, said liquid phase consisting essentially of a hydrocarbon solvent capable of completely evaporating at room temperature in a period of 5 minutes to 1 hour when the composition is applied to a carpet, water, and a water soluble surfactant dissolved in said water and capable of detergent action and characterized by the ability to dry to .a fiuffy residue.

References Cited UNITED STATES PATENTS 2,442,024 5/1948 Smith et al. 252l66 2,364,608 l2/l944 Edward 252l66 3,240,713 3/1966 Hulsh 252139 OTHER REFERENCES Thomas C. Gregory, Uses and Applications of Chemicals and Related Materials, vol. II, 1939.

LEON D. ROSDOL, Primary Examiner.

B. BETTIS, Assistant Examiner.

US. Cl. X.R. 252166, 168 

